Presentation and evaluation of the Arctic sea ice forecasting system neXtSIM-F

Abstract. The neXtSIM-F (neXtSIM forecast) forecasting system consists of a stand-alone sea ice model, neXtSIM (neXt-generation Sea Ice Model), forced by the TOPAZ ocean forecast and ECMWF atmospheric forecast, combined with daily data assimilation concentration. It uses novel brittle Bingham–Maxwell (BBM) rheology, making it first based on continuum model not to use viscous–plastic (VP) rheology. was tested in Arctic for time period November 2018–June 2020 found perform well, although there are some shortcomings. Despite drift being assimilated our system, is good throughout year, relatively unbiased, even longer lead times like 5 d. RMSE speed total also 3 or so days, they both increase steadily time. thickness distribution good, regions that experience excessive thickening negative implications summertime extent, particularly Greenland Sea. assimilates OSI SAF concentration products (both SSMIS AMSR2) modifying initial conditions adding compensating heat flux prevent removed growing back too quickly. greatly improves extent duration.